Currently, there is a probing test that measures an electric characteristic on two or more semiconductor chips, which are formed on a semiconductor wafer in such a way that a contact may quickly link with a terminal, such as lands or balls arranged on semiconductor chips. These contacts are known, including an electro conductive rubber, a so-called Pogo pin, a stamping spring produced by a die cutting processing, and a ring spring with an electroformed pipe. In the probing test, an interposer has an insulator, in which such contacts are mounted.
U.S. Pat. No. 5,573,435 discloses such a contact, wherein two independent unclosed loops are connected. The loops are prepared through a die cutting process. The proposed contact has a design that allows for high elasticity and low resistance, as well as low self-inductance in the low spring constant.
Moreover, the '435 reference proposes a connection body (contact) formed using a MEMS (Micro Electro Mechanical System) process (refer to Japanese Patent Publication TokuHyou 2006-514289, for instance). The contact, proposed by Japanese Patent Publication TokuHyou 2006-514289, has a first contact section where one end meets a semiconductor bump, a connection section that is C shaped and extending continuously from the other end to the one end of the first contact section, a support section that is connected with one end of the connection section and has a convex shape, and a second contact section that is inserted into an electric circuit board and has an O shape extending continuously from one end of the support section. The proposed contact may be prepared using micro processing, such as the MEMS process. Particularly, it is possible to prepare one end of the first contact section through micro processing, the first contact section that meets the semiconductor bump. Preparing the proposed first contact through die cutting section would be difficult to implement.
However, a contact prepared from electro-conductive rubber is inferior in durability. A contact that consists of Pogo-pin and the ring spring is inferior in the contact reliability. Moreover, a contact that consists of the stamping spring is difficult to implement miniaturization, because there is a limit in micro processing, and it is inferior in high density mounting and handling a high-speed signal.
According to the contact proposed by U.S. Pat. No. 5,573,435, two unclosed loops are formed, but are independent of each other. The amount of displacement is relatively small and the contact pressure increases in an interposer where the contact is mounted on the insulator.
It is difficult to minimize the shape of the proposed contact, especially considering that the two independent loops connect. However, it is necessary to reduce the loop in order to achieve maximum displacement and the low contact pressure. Moreover, since the connected structure of two independent loops is a structure joined in the center section, connection might broken when the contact is under a lateral load. Moreover, there is a problem in that the contact is inferior in a high-density mounting and high-speed signal to the insulator, because the contact is the one produced by a die cutting process.
According to the contact proposed by Japanese Patent Publication TokuHyou 2006-514289, an interposer, wherein the contact is mounted on an insulator, the amount of displacement depends only on a cantilever beam of a connection section. Accordingly, it is necessary to increase the thickness of the contact, for instance 100 μm or more, to obtain a large amount of displacement (to obtain a prescribed spring load). However, it is known that it takes a long time to form a contact having a thickness of 100 μm using the MEMS process, as much as 10 hours.